Sinking mattress

I had purchased an Edblo queen bed set on the 14 December 2024. The one side of the bed is shallow/sinking. When you make up the bed you can see the bed is not even. I weight 75Kg for the bed to have a shallow around where I sleep. I would like to exchange the bed. I thought if you leave it in the morning it will rise back to its normal form. Im not happy with the bed considering we paid cash for it and its supposed to be new and last us for 10years, at this rate I don’t see it. I have been emailing customer service since January no response